For improved laundry treatment, in particular for post-treatment after washing, it is advantageous to steam the laundry in the washing machine so as to remove wrinkles.
European Patent Document EP 1 659 205 A2 describes a front-loading washing machine including a suds container for receiving wash liquid and the laundry to be treated. The washing machine also includes a steam generator which has a heating element and is capable of receiving the liquid to be evaporated, said heating element being provided for heating and evaporating the liquid. The washing machine further includes a means for spraying or introducing water into the suds container, the means including a nozzle in the edge region of the door opening. In order to generate the steam, the heating element is heated to a predetermined temperature of, for example, at least 100° C., after which the liquid is introduced into the steam generator. In this manner, steam is generated in the form of bursts. After a predetermined time, the flow of water into the steam generator is stopped. After another predetermined time, the inflow of water is reactivated. This activation and deactivation of the inflow of water is repeated several times.
European Patent Document EP 1 655 408 A1 describes a similar washing machine having a device for generating steam. This steam generator device has a temperature sensor for controlling the inflow of water. When the temperature drops below a predetermined value, the flow of water into the steam generator device is reduced. When the temperature exceeds the predetermined value, the inflow of water is increased.
Furthermore, European Patent Document EP 1 813 709 A2 describes controlling the water inflow and the heating element of a steam generator device as a function of a predetermined temperature value. Here, the operating time of the steam generator device is also taken into account.
European Patent Document EP 1 464 751 A1 describes a washing machine having a suds container for receiving wash liquid and the laundry to be treated. The washing machine described therein includes a steam generator used for steaming the laundry. Here, the steam generator includes a tank into which a predetermined amount of water is introduced. A heating element heats the liquid until it evaporates. The steam is passed through a conduit and a nozzle into the treatment chamber, i.e., into the interior of the drum. Moreover, water can be passed into the interior of the drum through the same conduit and nozzle. The inlet is directly connected to the water supply and is controlled by a valve. Similarly, a discharge valve controls the discharge of steam so as to provide sufficient steam pressure within the steam generator device. When the discharge valve is opened, a large quantity of steam is discharged because of the high pressure, as a result of which droplets are carried out of the tank. However, during treatment of laundry with steam, droplets are not desired because they result in non-uniform wetting of the laundry.